For a while I've been thinking about extending header rewriting to the
Message-ID header, so as to not leak information about my internal network
out through the mail gateway. (If you are an anti-rewriting zealot, please
stop reading now!)
I have implemented this, and done some testing of it.
It can be turned on by using the "all-headers" flag, or by adding an 'i'
flag to the rewriting rule flags.
Fortunately someone else appears to also be interested, according to the
exim-users list archives, so I thought I'd share the patch.
Is this sufficient as a patch-submission process, or is there some
other address or list I should forward to? Please someone let me know.
(CC'd to debian maintainers and Jan-Peter as interested parties)
Patch is against 4.34 (from debian source package), but I have checked
visually against a pristine 4.44, and it should apply cleanly with offsets
--- src/rewrite.c.orig 2004-05-10 13:31:20.000000000 +0100
+++ src/rewrite.c 2004-12-17 21:28:28.000000000 +0000
@@ -20,7 +20,8 @@
" bcc",
"reply-to",
"env-from",
- " env-to"
+ " env-to",
+ " msg-id"
};
/* Structure and table for finding source of address for debug printing */
@@ -39,6 +40,7 @@
{ rewrite_replyto, US"reply-to:" },
{ rewrite_envfrom, US"env-from" },
{ rewrite_envto, US"env-to" },
+ { rewrite_msgid, US"message-id:"},
{ rewrite_smtp, US"smtp recipient" },
{ rewrite_smtp|rewrite_smtp_sender, US"smtp sender" }
};
@@ -745,6 +747,10 @@
case htype_reply_to:
return rewrite_one_header(h, rewrite_replyto, routed_old, routed_new,
rewrite_rules, existflags, replace);
+
+ case htype_id:
+ return rewrite_one_header(h, rewrite_msgid, routed_old, routed_new,
+ rewrite_rules, existflags, replace);
}
return NULL;
--- src/macros.h.orig 2004-05-10 13:31:20.000000000 +0100
+++ src/macros.h 2004-12-17 21:34:38.000000000 +0000
@@ -613,21 +613,22 @@
#define rewrite_cc 0x0008
#define rewrite_bcc 0x0010
#define rewrite_replyto 0x0020
-#define rewrite_all_headers 0x003F /* all header flags */
+#define rewrite_msgid 0x0040
+#define rewrite_all_headers 0x007F /* all header flags */
-#define rewrite_envfrom 0x0040
-#define rewrite_envto 0x0080
-#define rewrite_all_envelope 0x00C0 /* all envelope flags */
+#define rewrite_envfrom 0x0080
+#define rewrite_envto 0x0100
+#define rewrite_all_envelope 0x0180 /* all envelope flags */
#define rewrite_all (rewrite_all_headers | rewrite_all_envelope)
-#define rewrite_smtp 0x0100 /* rewrite at SMTP time */
-#define rewrite_smtp_sender 0x0200 /* SMTP sender rewrite (allows <>) */
-#define rewrite_qualify 0x0400 /* qualify if necessary */
-#define rewrite_repeat 0x0800 /* repeat rewrite rule */
+#define rewrite_smtp 0x0200 /* rewrite at SMTP time */
+#define rewrite_smtp_sender 0x0400 /* SMTP sender rewrite (allows <>) */
+#define rewrite_qualify 0x0800 /* qualify if necessary */
+#define rewrite_repeat 0x1000 /* repeat rewrite rule */
-#define rewrite_whole 0x1000 /* option bit for headers */
-#define rewrite_quit 0x2000 /* "no more" option */
+#define rewrite_whole 0x2000 /* option bit for headers */
+#define rewrite_quit 0x4000 /* "no more" option */
/* Flags for log_write(); LOG_MAIN, LOG_PANIC, and LOG_REJECT are also in
local_scan.h */
--- src/readconf.c.orig 2004-05-10 13:31:20.000000000 +0100
+++ src/readconf.c 2004-12-17 21:34:38.000000000 +0000
@@ -1018,6 +1021,7 @@
case 'c': next->flags |= rewrite_cc; break;
case 'b': next->flags |= rewrite_bcc; break;
case 'r': next->flags |= rewrite_replyto; break;
+ case 'i': next->flags |= rewrite_msgid; break;
case 'E': next->flags |= rewrite_all_envelope; break;
case 'F': next->flags |= rewrite_envfrom; break;
--
Peter Denison <peterd at marshadder dot org>
Please use this address only for personal mail, not copied to lists
gatewayed to news or web pages unless the addresses are removed.
